Alternate-action switch actuator with pawl stop plate also providing a guide for stroke-control means

ABSTRACT

A push-button key switch having an actuator movable within a hollow casing normally closed by a base plate that provides support for a fixed contact-bearing terminal and a second movable contact-bearing terminal as well as an actuator control plate which cooperates with a stroke-control member carried by and movable with the actuator, which movement results in alternate full and half strokes of the actuator, which in turn determine the making, maintaining, and breaking of circuit-making contact between the terminals.

United States Patent 1 Habecker NOV. 6, 1973 ALTERNATE-ACTION SWITCH ACTUATOR WITH PAWL STOP PLATE ALSO PROVIDING A GUIDE FOR STROKE-CONTROL MEANS [75] Inventor: John W. Habecker, Waukegan, Ill.

[73] Assignee: Cherry Electrical Products Corporation, Waukegan, 111.

[22] Filed: Jan. 14, 1972 [21] App]. No.: 217,838

[52] U.S. Cl. 200/153 .1, 74/532 [51] Int. Cl. 1101b 13/56 [58] Field of Search 200/153 J; 74/532 [56] References Cited UNITED STATES PATENTS 2,890,387 6/1959 Wiley et a1 200/153 J X 3,165,612 1/1965 Bailey 200/153 J UX Bury 200/153 J X FOREIGN PATENTS OR APPLICATIONS 1,087,667 8/1960 Germany 200/153 J 1,171,778 ll/l969 Great Britain 200/153 J Primary ExaminerRobert K. Schaefer Assistant ExaminerRobert A. Vanderhye Attorney-Edward C. Threedy [5 7] ABSTRACT A push-button key switch having an actuator movable within a hollow casing normally closed by a base plate that provides support for a fixed contact-bearing terminal and a second movable contact-bearing terminal as well as an actuator control plate which cooperates with a stroke-control member carried by and movable with the actuator, which movement results in alternate full and half strokes of the actuator, which in turn determine the making, maintaining, and breaking of circuitmaking contact between the terminals.

3 Claims, 6 Drawing Figures ALTERNATE-ACTION SWITCH ACTUATOR WITH PAWL STOP PLATE ALSO PROVIDING A GUIDE FOR STROKE-CONTROL MEANS SUMMARY OF THE INVENTION A push-button type key switch having normally closed circuit-making contacts physically held apart by a cam-faced actuator movable relative thereto. The actuator carries a stroke-control star wheel cooperating with a control plate providing a star wheel retaining pawl that alternately controls the length of the return stroke of the actuator between a full normal position and a half stroke-actuating position, the former being provided so that the contacts will remain in relative position one to another until a subsequent movement or stroke of the actuator occurs.

GENERAL DESCRIPTION The invention is shown in its most preferred embodiment in the accompanying drawings, in which:

FIG. 1 is a perspective view of a push-button key switch;

FIG. 2 is a detailed sectional side elevational view of the switch housing and the components positioned therein in their normal or unactuated condition;

FIG. 3 is a fragmentary detailed sectional view similar to FIG. 2, showing the parts thereof in their arrested or first actuated position;

FIG. 4 is a perspective view of certain of the components and parts of the switch shown in an exploded relation with respect to each other;

FIG. 5 is a detailed sectional view showing the strokecontrol apparatus of the switch in its normal position and showing in dotted lines a partially actuated position;

FIG. 6 is a detailed sectional view showing the parts of FIG. 5 in their arrested or first actuated position and showing in dotted lines a partially actuated position.

FIG. 1 discloses a push-button type key switch 10 which may be readily used in what is known as keyboard equipment utilized in computers, data processing machines, calculators, and electric typewriters.

The switch 10 includes a hollow housing 11 normally closed by a base plate 12. The top wall 13 of the housing provides a generally rectangularly shaped opening 14 through which the plunger 15 of the switch actuator is freely journalled. The exposed end of the plunger 15 carries an actuating button 16, which may be of any design or configuration.

The base 12 supports in a vertical position a fixed terminal 17 which provides at one end a terminal mount 18 adapted to be projected through the base 12 when the terminal 17 is mounted within the retaining groove 19 provided by the base 12.

A second terminal or switch blade 20 is adapted to have its base portion 21 mounted within the groove 22 provided by the base 12, with its terminal mount 23 projecting therethrough, as shown in FIGS. 1, 2 and 3.

The free end 24 of the second terminal 20 provides a contact 25 which when in a circuit-completing posltion, engages contact 26 carried by the confronting face of the terminal 17. In the assembly shown, the terminal 20 is normally bent out of its longitudinal plane so as to be biased in the direction of the terminal l7,

so that the contacts 25 and 26 thereof normally will be engaging each other and thus completing a circuit through the terminals 17 and 20.

The terminal 20 provides a pair of laterally extending arms 27 which provide at their free end, arcuated cam faces 28. These cam faces 28 have continuous engagement with the cams 29 carried by a movable switch actuator 30.

The switch actuator 30 includes the rectangularly shaped plunger 15 as well as a base portion 31 which is of a width greater than that of the plunger 15 which supports the laterally projecting cams 29, all of which is clearly shown in FIG. 4. The bottom edge of the actuator 30 is notched to either side of a stud 32 which is adapted to be projected within the confines of the coils of the spring 33, with the spring 33 normally functioning to maintain the actuator 30 in its normal or unactuated position, as shown in FIG. 2. Mounted on the other side of the actuator .30 is a stroke-control star wheel 34. This star wheel is freely pivoted on a shaft 35 which is securely attached to an opening 36 formed in the body of the actuator 30, and which shaft provides a hub 37. Each arm 39, 40 and 41 of the star wheel 34 has its extremity notched to provide a trip member 42 and cam finger 43 for a purpose hereinafter made apparent.

Also carried by the base 12 and extending in a spaced parallel relation to the terminals 17 and 20 as well as the actuator 30, is a stroke-control plate 44. This plate 44 is substantially hollowed out and has a portion of one wall 45 and one side edge wall portion 46 and part of its top wall 47 removed to provide access to an interior cavity 48. The partially removed side wall 46 provides a pawl 49 which extends inwardly from said side wall and is disposed in the path of travel of the arms of the star wheel 34. The top wall 47 of the plate 44 provides a stop 50 which extends in the direction of the pawl 49 and which also lies in the path of movement of the arms of the star wheel 34. The rear wall 51 of the plate 44 provides an elongated channel 52 which receives the hub 37 of the shaft 35.

When the switch and its actuator are in normal position, the components will be related to one another as seen in FIGS. 2 and 5. In such position, the cams 29 of the actuator 30 will have their apexes in contact with the cam faces 28 of the lateral arms 27 of terminal 20, physically separating its contact 25 from contact 26 of the fixed terminal 17. However, it should be noted that if the cam faces 28 of the arms 27 when so positioned on the terminal 20, as to contact the cams 29 at a point below the latters apex as shown, the contacts 25 and 26 would in their normal position be in contact with each otherv and separate upon movement of actuator 30. The star wheel 34 will be in the position shown in FIG. 5, wherein its first arm 39 projects above the top wall 47 of the control plate 44. As the actuator 30 is depressed, it will carry the star wheel 34 in a downward direction until the trip member 42 of the second arm 40 engages the pawl 49 and, by continuing downward movement, the star wheel 34 will be caused to rotate, in a counterclockwise direction as shown in FIG. 5, a limited degree such that the first arm 39 will be in a position where one wall 53 of its carn finger 43 engages the end 54 of the stop 50 when the actuator is pennitted to move in a return direction, with the parts assuming the positions shown in FIG. 6.

With the parts in the position shown in FIG. 6, the actuator 30 has returned a half stroke and consequently the cam faces 28 of the terminal 20 are still in contact with a sufficient portion of the earns 29, such that the contact 25 of the terminal 20 remains in engagement with the contact 26 of the terminal 17, maintaining an electrical circuit therethrough.

Upon a second depression of the actuator 30, the pawl 49 of the stroke-control plate 44 will engage the wall surface 55 of the cam finger 43 of the second arm 40, causing the star wheel 34 to rotate a sufficient distance such that the first arm 39 will be disposed completely beneath the stop 50 so that when the actuator 30 completes its downward travel and starts its return stroke, the wall surface 56 of the cam finger 43 of the first arm 39 will engage the undersurface S7 of stop 50, causing an additional rotation of the star wheel 34 such that the second arm 40 will now be in the position that was occupied by the first arm 39, with the components in the condition shown in FIG. 5.

From the foregoing it is apparent that a stroke control structure has been described which permits a switch of this character to have a first actuation whereby its circuit-making contacts are closed and wherein such completed circuit will remain until a subsequent stroke of the switch actuator occurs. In the embodiment shown and described in this application, the desired result is accomplished by restricting the return stroke of the actuator between a full return position and a half-return position.

While I have illustrated and described the preferred form of construction for carrying my invention into effect, this is capable of variation and modification without departing from the spirit of the invention. I, therefore, do not wish to be limited to the precise details of construction set forth, but desire to avail myself of such variations and modifications as come within the scope of the appended claims.

Having thus described my invention, what I claim as new and desire to protect by Letters Patent is:

1. An alternate-action switch actuator reciprocally movable through a housing including a pair of circuitmaking contacts carried by spaced apart currentconducting terminals, one of which is stationary and the other of which is movable relative thereto by the actuator, wherein the improvement comprises a. an elongated actuator having a normal position and a linear stroke path reciprocally through the housing,

b. a stroke-control means rotatably carried by and movable with said actuator for controlling the length of movement of said actuator through the housing,

c. a stroke-control plate within said housing and extending in a spaced parallel relation to the path of movement of said actuator,

d. said plate providing a pawl in the path of movement of said stroke-control means for rotating the same during each stroke of said actuator in one direction,

e. a stop carried by said plate in a parallel vertical spaced offset relation to said pawl and extending in an opposite direction with respect thereto,

f. said stop being disposed in the path of rotatable movement of said stroke-control means after the same has been initially rotated by said pawl for arresting movement of said actuator in an opposite direction upon each alternate stroke of said actuator in said one direction, and

g. said plate providing a guide for said stroke-control means for guiding the reciprocal stroke of said actuator and said stroke-control means within said housing.

2. An alternate-action switch actuator as defined by claim 1 wherein said stroke control means comprises a star wheel rotatably mounted on said actuator and having a plurality of equally spaced radial arms, each arm having a head providing a trip member and a cam finger which successively contact said pawl to rotate said star wheel during each stroke of said actuator in one direction, said trip member rotatable into contact with said stop by each alternate stroke of said actuator in one direction for controlling the length of movement of said actuator in said opposite direction.

3. An alternate-action switch actuator as defined by claim 2 and including means rotatably connecting said star wheel onto one side of said actuator, said means comprising a stud having an enlarged head, with said head cooperating with a guide provided within the housing for guiding the reciprocal movement of said actuator. 

1. An alternate-action switch actuator reciprocally movable through a housing including a pair of circuit-making contacts carried by spaced apart current-conducting terminals, one of which is stationary and the other of which is movable relative thereto by the actuator, wherein the improvement comprises a. an elongated actuator having a normal position and a linear stroke path reciprocally through the housing, b. a stroke-control means rotatably carried by and movable with said actuator for controlling the length of movement of said actuator through the housing, c. a stroke-control plate within said housing and extending in a spaced parallel relation to the path of movement of said actuator, d. said plate providing a pawl in the path of movement of said stroke-control means for rotating the same during each stroke of said actuator in one direction, e. a stop carried by said plate in a parallel vertical spaced offset relation to said pawl and extending in an opposite direction with respect thereto, f. said stop being disposed in the path of rotatable movement of said stroke-control means after the same has been initially rotated by said pawl for arresting movement of said actuator in an opposite direction upon each alternate stroke of said actuator in said one direction, and g. said plate providing a guide for said stroke-control means for guiding the reciprocal stroke of said actuator and said stroke-control means within said housing.
 2. An alternate-action switch actuator as defined by claim 1 wherein said stroke control means comprises a star wheel rotatably mounted on said actuator and having a plurality of equally spaced radial arms, each arm having a head providing a trip member and a cam finger which successively contact said pawl to rotate said star wheel during each stroke of said actuator in one direction, said trip member rotatable into contact with said stop by each alternate stroke of said actuator in one direction for controlling the length of movement of said actuator in said opposite direction.
 3. An alternate-action switch actuator as defined by claim 2 and including means rotatably connecting said star wheel onto one side of said actuator, said means comprising a stud having an enlarged head, with said head cooperating with a guide provided within the housing for guiding the reciprocal movement of said actuator. 